To obtain the maximum production from a field of hay, each crop of hay must be promptly cut, baled and removed from the field. The more quickly hay can be cut and removed, the more quickly a successive crop of hay can be cultivated.
The harvesting of hay involves three main tasks: 1) cutting the hay; 2) baling the hay; and 3) removing and storing the baled hay. Although originally manual tasks, nowadays these tasks have to a great extent been mechanized. Three types of equipment are usually involved. A swather cuts the hay and deposits the cut hay in rows. A baler scoops up the cut hay and compresses the hay into rectangular bales. A stacker picks up individual bales of hay from the field, accumulates a predetermined number, and deposits the accumulated bales off the field at a storage location.
Of these three tasks, the removing and stacking of the hay bales has heretofore been the most cumbersome.
The difficulties involved in removing and stacking hay bales are to a great extent dependent on the size and quantity of individual bales produced by the specific hay baler that is used. Until recently, hay balers have come in three common sizes, producing the following three sizes of bales: (1) 14" by 16" by 3 or 4 feet long; (2) 16" by 18" by 3 or 4 feet long; and (3) 16" by 24" by four feet long. These three sizes collectively fall in the category of "small bales". More recently, balers capable of producing larger bales of hay have been introduced. The bales produced by these new balers are typically 8 feet in length and have cross sections of 2 by 3 feet, 3 by 4 feet, or 4 by 4 feet. The advantage of these new larger bales is that a given amount of hay can be packed in a significantly smaller number of bales: a 4 by 4 by 8 foot bale of hay is 12 times the size of a 16" by 24" by four foot bale. As few as 1/12 as many "big bales" as compared to small conventional bales are needed to bale a given amount of hay. Fewer bales means less time spent gathering, stacking and moving bales. Another advantage of "big bales" is that they minimize the time needed to transfer a given amount of hay from a stack to a semi-truck for transport. They also result in a more stable and efficient load.
One factor limiting the use of "big bale" balers is the lack of effective machines designed to pick up, transport, stack and retrieve the big bales.
The most common method used for moving "big bales" from the field to a storage area (or to a stack) is to use a tractor with a front end loader attachment together with a flatbed truck and/or a flatbed trailer. The tractor uses the front end loader to load the "big bales", one by one, onto the truck or trailer. The truck or trailer is then driven to the storage area, and unloaded by the same or a second tractor. The bales are accumulated into stacks as they are unloaded by the tractor. For this method of stacking "big bales", two or more pieces of equipment (a tractor and a truck or trailer) and at least two operators (one for each piece of equipment) are required.
Although prior art "big bale" stackers have been developed, they have had little impact at displacing the above tractor/trailer method because they are either slow, awkward to use, have small payload capacities, and/or create unstable stacks of bales.
One prior art stacker is shown in FIG. 1. It basically consists of a self-propelled truck platform 20 outfitted with a control cabin 25, a conveyor 30, and a tippable bed 40. This type stacker loads bales by driving up to a bale 50 such that teeth 35 of the conveyor's chain belt engage the rear of bale 50 and pull it up the conveyor. When the bale gets to the top of the conveyor 30, it is dumped on end into bed 40. Hydraulic rams or other means mounted to the bed push the bale to the side to make room for the next bale of hay. After the second bale is deposited next to the first, these two bales are pushed back by hydraulic or other means to make room for the second set, or "tier" of bales. The bed of this kind of stacker typically holds six 4 by 4 by 8 foot "big bales" of hay: 3 rows of two bales each stood up on end. Alternatively, this kind of stacker may hold eight 3 by 4 by 8 foot bales arranged in 4 rows of two bales each stood up on end. The stacker shown in FIG. 1 is shown with a partial load 55 consisting of four bales of hay.
Once the bed is filled with a load of six bales of hay, the stacker can be driven to the edge of the field or to wherever it is desired to deposit the hay. To unload the bales, the bed 40 of the stacker tips back as indicated by the arrow in FIG. 1, such that the load of bales is tilted up 90 degrees. Hydraulic "push-off feet" force the stacker out from under the newly formed stack. A resultant three tiered stack 60 is formed.
Because of the way this type of stacker deposits stacked bales (i.e. loading and unloading off its back end) and the way in which the bales are retrieved by the conveyor and stored in the bed (i.e. on end), the type of stack formed by successive loads has the configuration shown in FIG. 2: essentially two columns, three bales high, arranged lengthwise side by side. Because there is no supporting means on the outside sides of the bales, and because of the narrow base "B" of the bales, this configuration tends to be unstable. As a result, as the bales dry out and start to shrink, the top bales 80 are often dislodged, as shown by the arrows in FIG. 2.
In a second prior art big bale stacker, instead of conveyor 30, a hydraulic articulated crane boom with a claw-type grabber is used to grab, lift and load bales onto the loading bed. This embodiment has the advantage that it can make "tied" loads (loads in which the orientation of alternating tiers of bales differ by 90 degrees), it can retrieve and stack all three "big bale" sizes, and can retrieve bales one at a time. The boom can also be used to unload bales directly from the stacker onto a truck, or the bed can be tilted to deposit the bales in the same manner as the stacker shown in FIG. 1. Disadvantages of this type of stacker are (1) it is complex and expensive to manufacture; (2) it requires extensive skill to operate; (3) since each bale must be individually grabbed by the boom, it has a slow loading time; and (4), like the previous embodiment, it has a limited load capacity.
A third type of prior art "big bale" stacker is shown in FIG. 3. This kind of stacker basically consists of a flatbed truck 120 with two large "forks" 130 pivotably attached to the back of the bed. Forks 130 are initially lowered near the ground. The truck 120 lines up in front of a bale of hay and backs up, pushing the forks under the bale. The forks of the stacker shown in FIG. 3 have a capacity of two bales. After the first bale has been loaded, the forks 130 are lifted slightly off the ground and the stacker drives to the next bale, where the action is repeated. The stacker shown in FIG. 3 is shown with one bale 140A already on its forks as it is about to load a second bale 140B. After the second bale has been loaded onto the forks, the forks are pivoted upwards 90 degrees, depositing the two bales picked up by the forks on the truck's bed 160. Any bales 150 already on bed 160 are pushed back along the bed by the new bales being deposited. When the bed is full (the stacker illustrated has a capacity of eight bales), the stacker is driven to the area where it is desired to deposit the bales and the bales are unloaded using the same general method described in relation to the stacker shown in FIG. 1, with the exception that no "push-off feet" are required.
Since the bales in this prior art stacker are loaded onto the stacker's bed on their sides rather than on their ends (as in the stacker of FIG. 1), the configuration of the stack resulting from multiple loads of bales, as shown in FIG. 4, consists of a single four-tiered row of bales sitting crosswise, instead of the two narrow side by side columns shown in FIG. 2. This arrangement is much more stable than the arrangement shown in FIG. 2, although the outermost ends of the stack 180 shown in FIG. 4 still tend to be unstable. Another disadvantage of this kind of stacker is that a bale-turning apparatus must be affixed to the rear of the baler to make sure that the bale is deposited on the ground on its non-string side (a baler generally forms the bale and then secures it with a string). Otherwise the bale strings would be damaged or cut when the stacker's loading forks are slid under the bales when they are being loaded or unloaded from the stacker.
In an alternative prior art embodiment of the stacker shown in FIG. 3, the forks are not located on the back of a truck but are instead mounted on the front of a trailer that can be towed by a tractor. This embodiment is easier to use than the truck (since bales can be loaded by driving forwards rather than backwards), but it has only one-half the payload capacity, and is limited to slow transporting speeds.